lipopolysaccharide Syllabification: (lip·o·pol·y·sac·cha·ride)Pronunciation: /ˈlipōˌpälēˈsakəˌrīd, ˈlī-/Definition of lipopolysaccharide noun Biochemistry a complex molecule containing both lipid and polysaccharide parts. lipopolysaccharide in other Oxford dictionaries Definition of lipopolysaccharide in the British & World English dictionary